In general, an air conditioner consumes much power at the peak of power consumption on a hot day in summer or the like. At the peak of the power consumption, when a set temperature of each air conditioner is merely raised as much as 2° C. to 3° C., power saving is noticeably realized. To realize the power saving, a demand side management (DSM) such as a load control system is suggested in which a power company and the like regulate the power consumption of an electric device (including the air conditioner) for a household, an office building and the like by remote control. Specifically, industry organization ‘Echonet Consortium’ for household apparatus control has started a demonstration experiment of a DSM service in Tokyo from November of 1999.
Examples of a control method concerning DSM include a restricting or peak cutting of the whole power load by forced load blocking (selective load blocking), and leveling of the load by a shift of the load use period of time. In a load adjustment logic of these control methods, a priority of the load to be blocked and an adjustment rule of the load need to be beforehand determined. This load adjustment logic is a unilateral energy management technology in which the state of the energy demand device is not taken into consideration.
Moreover, there is suggested a technology in which supply of energy from an energy supply device to energy demand device is managed only by the energy supply device. Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2002-10532) discloses an energy management system which manages the supply of the energy to the energy demand device. In Document 1, however, unilateral demand control from the energy supply device to the energy demand device is performed, and hence any request from the energy demand device to the energy supply device is not reflected.
Furthermore, in a demand prediction of the load in demand control such as a microgrid technology, load adjustment is not performed, but the demand is predicted by taking an operation of the load as a top priority into consideration. Therefore, in the demand control or operation planning, a limit of the adjustment is strictly determined, and the operation is difficult sometimes. To cope with these difficulties, facilities such as a privately owned power facility, a fuel cell and a power storage apparatus (an accumulator) for executing demand matching need to be beforehand installed, which increases costs.